Graphics, Figures & Tables ⇒ Customize uparrow and downarrow

[bstex]

Hi.
I'm using the mhchem package and I'd like to have custom arrows in my text.
Rightarrow, leftarrow and doublearrow are fine with my custom design, but why uparrow and downarrow are not shown with my custom design?

Screen Shot 2018-06-21 at 18.55.57.png (13.93 KiB) Viewed 6258 times

My MWE:

Code: Select all

\documentclass[a4paper,11pt]{book}
\usepackage{tikz}
\usetikzlibrary{positioning,arrows.meta}
\usepackage[version=4]{mhchem}

\begin{document}

\ExplSyntaxOn
\cs_set:Npn \__mhchem_arrow_options_minLength:n  { {1.25em} }
\ExplSyntaxOff

\mhchemoptions{arrows=pgf{Straight Barb[round, angle=60:1.5pt 3]}{0.1ex}}
\ce{A -> B} \\
\ce{C <- D} \\
\ce{E <=> F} \\
\ce{G ^} \\
\ce{H v} \\

\end{document}

Thank you very much.

[Stefan Kottwitz]

mhchem does the customization only for horizontal arrows.

Here is a quick idea, taking the customized arrows and rotating them:

Code: Select all

\renewcommand{\uparrow}{\raisebox{0.3ex}{\rotatebox[origin=c]{90}{\ce{->}}}} 
\renewcommand{\downarrow}{\raisebox{0.3ex}{\rotatebox[origin=c]{-90}{\ce{->}}}}

mhchem.png (10.13 KiB) Viewed 6219 times

Stefan

[bstex]

Pretty good, but this way the uparrow and downarrow have a little bit larger length than they should.

Screen Shot 2018-06-23 at 16.05.12.png (8.74 KiB) Viewed 6216 times

Since the length of the arrows is defined in preamble with:

Code: Select all

\ExplSyntaxOn
\cs_set:Npn \__mhchem_arrow_options_minLength:n  { {1.25em} }
\ExplSyntaxOff

is it possible to make shorter only the up and down arrows?
Thank you Stefan for your reply.

[Stefan Kottwitz]

The arrow could be scaled so it has the same proportions as the horizontal one:

Code: Select all

\renewcommand{\uparrow}{\scalebox{0.68}{\raisebox{0.75ex}{\rotatebox[origin=c]{90}{\ce{->}}}}}
\renewcommand{\downarrow}{\scalebox{0.66}{\raisebox{0.78ex}{\rotatebox[origin=c]{-90}{\ce{->}}}}}

Stefam

[bstex]

That's a solution, sure, but I need to shorten only the length of the arrow, not to shrink it.
Thank you again.

[Stefan Kottwitz]

Ok...

Code: Select all

\ExplSyntaxOn
\renewcommand \uparrow {
  \raisebox {0.4ex} {
  \rotatebox [origin=c] {90} {
  \cs_set:Npn \__mhchem_arrow_options_minLength:n  { {0.85em} }
  \ce{->}}}
}
\renewcommand \downarrow {
  \raisebox {0.4ex} {
  \rotatebox [origin=c] {-90} {
  \cs_set:Npn \__mhchem_arrow_options_minLength:n  { {0.85em} }
  \ce{->}}}
}
\ExplSyntaxOff

mhchem-arrows.png (10.54 KiB) Viewed 6210 times

Stefan

[bstex]

Oh, that was too complex for me to do.
Thank you very much, Stefan.